How To Gut A Catalytic Converter Without Removing It?


The most common approach to hollowing out a catalytic converter is removing it entirely from the vehicle. Still, some car owners would prefer doing that without removing it from the car. But is that possible?

Yes, you can gut a catalytic converter without removing it from the vehicle. You’ll have to raise the vehicle high off the ground using a pneumatic lift to do that. Then, cut a flap in the converter’s base and bend it open to access its insides. Gently chip away at the contents before folding the flap and welding it shut.

This article will teach you everything you need to know about this process. First, you’ll learn what tools are required before going through a step-by-step process to gut your catalytic converter.

Let’s get started.

Is It Legal To Hollow A Catalytic Converter?

If you’re reading this article, you probably already know that hollowing out a catalytic converter is legally questionable. In many places, if not most of them, local road authorities forbid you from doing so.

That’s because the catalytic converter ensures your car doesn’t emit too many harmful emissions into the surrounding environment. 

As you can imagine, anything to do with your car’s emissions is heavily regulated in this day and age of environmental consciousness.

So, before you decide to gut your catalytic converter, be sure to check with your local rules and regulations to confirm whether or not it’s illegal to do so.

Read: How To Fix a Catalytic Converter Without Replacing It

What Tools Do You Need To Gut A Catalytic Converter?

The process of gutting a catalytic converter is time-consuming. That’s especially true if you want to do it without removing the part from your car.

So, there are several tools you’ll need to get the job done successfully.

Here are the tools you’ll need to gut a catalytic converter without removing it from your vehicle:

These are essential tools you’ll need to work on your catalytic converter from underneath your vehicle. Naturally, you’ll want to use any other tools you have in your workshop that make the job easier.

Read: How To Tell If a Catalytic Converter Is Clogged

How Do You Gut A Catalytic Converter Without Removing It?

Hollowing out your catalytic converter without removing it from your vehicle is possible. However, it does come with its fair share of challenges.

Here’s a 5-stop process you can follow to gut a catalytic converter without removing it:

Step 1: Locate And Identify The Catalytic Converter

The worst thing you’ll want to do is to mistakenly cut into a component that’s not the catalytic converter. That’s why this process’s first step is to correctly locate and identify the converter.

That process begins with a pneumatic lift lifting your vehicle high off the ground. Doing so will also provide you and your tools with plenty of space to work in the later steps of this process.

The converter’s precise location will differ between car models. Still, you’ll find it near the engine block in front of the muffler on most cars.

The car owner’s manual can often be a helpful resource. Typically, manufacturers will include information to help you identify the vehicle’s parts for repairs and maintenance.

Read: Is It A Good Idea Driving With A Bad Catalytic Converter?

Step 2: Cut The Converter Base To Create A Flap

Once you’ve confirmed the location of your catalytic converter, you can start the gutting (or ‘hollowing’ process).

Many people’s first instinct is to cut a square hole directly underneath the catalytic converter. However, that’s not the most practical way to approach it.

Instead, use a wheel grinder or welding torch to cut two or three right-angle lines into the converter’s base. Those lines will allow you to create a flap in the base by bending the metal using pliers and a crowbar.

More importantly, as you’ll discover in Step 4 below, cutting into the base makes it much easier to seal the catalytic converter again at the end of this process.

Read: What Is An Exhaust Leak?

Step 3: Gently Chisel The Contents Of The Converter

Creating the flap in the converter base is crucial as it gives you access to its insides. So, once you reach this step, you’ll be ready to perform the task of hollowing the catalytic converter.

Using a chisel and a hammer, you’ll want to gently chip away at the catalytic converter’s lining and its contents.

There are two essential things to remember here. Firstly, you only need to tap the chisel lightly to break the materials inside, including the ceramic that forms the slices inside. The process is time-consuming, but gentle taps allow you to hollow the converter without damaging it or any other part of your vehicle.

Secondly, the parts you chip away inside the converter will fall straight to the ground. So, you’ll want to do it at an angle to ensure none of it falls directly onto your face.

Read: What Happens if You Put Diesel in a Gas Car?

Step 4: Shut The Flap And Seal The Converter

After chipping everything away, you’ll find that you’ve successfully hollowed out your catalytic converter. Better yet, you did it without ever removing it from your car. 

Despite that, the job isn’t done just yet. You’ll still have to seal the converter back up again.

In Step 2, you used pliers and a crowbar to bend the metal flap open. Now, you’re going to do the opposite. Using the same pliers, bend the flap back to its original position.

Next, use a welding torch or something equivalent to weld the flap shut. In doing so, you’ll permanently seal the catalytic converter, preventing exhaust gasses from leaking when the engine starts again.

While the welding is still hot, you can use a metal putty knife to smoothen everything out. That’ll give the catalytic converter a nice and smooth finish.

Step 5: Inspect The Catalytic Converter

After sealing the catalytic converter, the final step of this process is to inspect and test the catalytic converter. If the job is done correctly, there should be absolutely no leaking of exhaust gasses whatsoever.

You can test the converter by running the engine. Firstly, look for any noticeable leaks throughout the catalytic converter. Be sure not to touch it with your bare hands because the converter can run quite hot and injure you.

As you perform that visual inspection, you must also listen out for any noises. Sounds like rattling, echoing, or hissing can all indicate a problem with the converter. The most likely issue is that you failed to weld the metal flap perfectly shut in Step 4.

You can shut the engine off and correct the mistake. Additionally, you can add cold-welding epoxy as a solution to seal any minor leaks.

Final Thoughts

Overall, gutting a catalytic converter without removing it from the vehicle is possible. However, the process requires a lot of equipment to perform correctly.

Firstly, you’ll need a pneumatic lift to raise the vehicle enough to perform the task. Then, you’ll cut a flap in the converter’s base to access the materials inside.

Once inside, chip away at all the contents until the catalytic converter is hollowed out.

Finally, seal the converter by welding that flap back into place. Don’t forget to check for leaks!

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